The present disclosure relates to a belt transmission system.
Two automatic tensioners (hereinafter simply referred to as an AT or ATs) are mounted in some belt transmission systems including an internal-combustion engine, a generator, and a starter motor. In particular, one of two ATs, which is located between a crank pulley and a generator, needs to exhibit high damping characteristics at the start of the generator and the starter motor. Hydraulic ATs are thus increasingly used.